The present invention relates to a cup for coffee, or similar drinks formed of synthetic thermoplastics material and comprising an inner frusto-conical hollow portion which diverges upwardly to the circular top of the cup and provided with a base having a spherical cap surface which is arched inwardly, an outer hollow frusto-conical portion which diverges downwardly from the top of the cup, this outer portion being provided with an outward shoulder attached peripherally at its lower edge to a section of wall, in which said shoulder, said section of wall and said edge constitute the unit stacking height of the outer portion and in which the inner portion has a greater height than the outer portion.
Cups of this type have the disadvantage that they cannot be stably stacked. The slight play between one cup and another in a stack, which is necessary so that the cups do not become stuck one within another, makes it easy for the upper cups in a stack to be displaced out of line, for example, when the top cup is taken from the stack for use, or for example, when a stack is moved from one place to another. Such displacement causes the stack to lean over and can cause it to fall.
Another disadvantage is that due to the low stability of each individual cup, caused by the fact that the lower edge of the outer portion is at a distance from the plane supporting the cup, the cup can be tipped over and the contents spilled.
Another disadvantage lies in the fact that a stack of cups of this type has a lateral surface consisting of a series of frusto-conical surfaces, and this gives rise to difficulties when printing frusto-conical surfaces due to discontinuities in the available surface.
An object of the invention is to at least minimize such disadvantages.